Apparatus for effecting ionization in gases



iv- Kw ll} 5 H v ii -213311. KR ami m'fsei y 1937- G. BRION El AL2,085,735

APPARATUS FOR EFFECTING IONIZATION IN GASES Original Filed Nov. 30, 19313 Shuts-Shoot l i. l 12 16 12 I T- K 1 I l l I I I l l v 1 1 1 1 i E 1111 l I 1 73 15 43 1 {4'2 4'1 4 11 74" 21 x I 1 w 17 24 11 24 Wm 2s s 1/28 \NVENT Geor Brio d ArthurJ nes rutgsch. I BY ATTORNEYS Examiner y1937- G. BRION ET AL 2,085,735

APPARATUS FOR EFFECTING IONIZATION IN GASES Original Filed Nov. 30, 19313 Sheets-Sheet 2 lNVENTORS Georg Brion a Arthur Johannes Krufisch,

BY *M' ATTO RN EYS s. BRION ET AL 2,085,735

APPARATUS FOR EFFECTING IONIZATION IN GASES Original Filed Nov. 30, 19313 Sheets-Sheet 3 July 6, 1937.

Z3 nvvewroes 106 Georg Brim d 8 Arthur/Mame: lfrut sc/z.

Arne/vars.

Patented July 6, 1931 UNITED STATES PATENT OFFICE Georg Brion. Freiberg,and Arthur Johannes Krutzsch, Munich, Germany, assignors toInternational Precipitation 00., Los

Calif.

Angeles,

Application November 30, 1931, Serial No. 578,165

Renewed October 15, 1936. In Germany December 4, 1930 6 Claims.

This invention relates to a new or improved arrangement for theproduction of ionization by impact, which is particularly valuable forelectrical gas purifying plants, in which the strength of the fieldrequired for ionization by impact is produced by means of a voltageproduced in a zone situated at the side of the charging and separatingzones, and the charge carriers so formed are conveyed by means ofanother voltage into the charging zone.

The invention permits of the production of large ionization surfaceswhich are cheap in manufacture and reliable in action and in particularare proof against sparking'across and in which an intense and uniformionizing layer or zone can be produced with comparatively low voltages.At the same time the invention permits of the construction of plants ofany desired size without there being any risk of the action of thesurfaces being impaired by the deposit of large quantities of dustthereon.

The arrangement also permits of a favourable superimposition orstratification of the fields required for the carrying out of the gaspurifying process and produced by different voltages. This secures anexcellent utilization of the ionizing area and consequently acomparatively low consumption of energy and but little electrical strainon the material.

According to the invention the superficial impact ionization area isproduced at the boundary or surface of a layer, preferably a plate,composed of insulating material, which separates the ionizationelectrodes of the difierent polarities from each other.

The idea on which the present invention is based may be carried out invarious ways. In preferred embodiments of the invention the ionizationelectrodes are constructed in the form of rods or linear conductors andlie on or in the vicinity of the surface of plates or other bodiescomposed of insulating material.

In a further preferred embodiment of the invention the layer ofinsulating material, which separates the ionization electrodes of thedifferent polarities is made cylindrical. The ionization electrodes ofthe one polarity may in such case form the core or an external jacket ofa cylinder or of a tube composed of insulating material, on the externaljacket surface of which the conductors of the other polarity, preferablyof linear form, are arranged. One electrode or several electrodes or oneseries of one polarity of the ionization electrodes or both series maybe embedded near the surface in the layer or the plate or other bodycomposed of insulating material; or ionization electrodes may bearranged on the surface of the layer of insulating material, and theelectrodes may be attached thereto in a suitable manner. The electrodes5 may consist of conducting materialqfani de-T' mm; and they may also beattached to the surface as thin conducting layers by sprayingfbu'rning,painting or may be laid on or cemented on or otherwise applied. 0n theother 10 5 Any suitable non-conducting,

ware, clay,,flre clay, cement, concrete, slate, '20

steatite ifiica or other mica or resin products oi rubber products; alsohard paper or any other natural or artificial immaterial. The

badly conducting substances may be solid but may also be liquid, inwhich case they are kept 25 in the form of layers in a suitable manneras by means of vessels for example.

The invention further resides in the features of construction and thearrangements and combinations of parts hereinafter described in detailand succinctly claimed, reference being had to the accompanyingdrawings, wherein:

Fig. 1 shows in section a dust precipitating arrangement according tothis invention.

Fig. 2 shows a detail of Fig. 1 on an enlarged scale,

Figs. 3 and 4 show in section and elevation respectively an arrangementaccording to this invention, in which rod-shaped conductors are embeddedin a plate of insulating material near the surface thereof.

Figs. 5 and 6 show arrangements in which conductors are arranged on thesurface of a plate of insulating material.

Figs. '7 to 9 show in section, and

Fig. 10 in perspective arrangements in which rod-shaped or linearconductors are arranged on the surface as well as in the interior of theplate.

Fig. 11 shows in section an arrangement with rod-shaped conductors onthe surface of a plate of insulating material and with a plate-like bodyof conducting material within the plate of insulating material.

Fig. 12 shows a similar arrangement in section, and

Fig. 13 the same in elevation, in which the plate-like body electricallyconnected within the insulating body acts as an electrode.

Fig. 14 shows another example of the application of this invention to adust precipitating plant.

Figs. 15 and 16 show in section and in perspective a dust precipitatingapparatus, in which the body of insulating material is constructed inthe form of a tube.

Fig. 17 shows a modification of this arrangement in section while Fig.18 shows an arrangement in section with tubular precipitatingelectrodes.

Fig. 19 shows a further modification of this .arrangement in section,while Figs. 20 and 21 show in perspective two modifications of thearrangement of the outer ionization electrodes on a tubular orcylindrical ionization body.

Fig. 22 shows in section a further modification of a precipitatingarrangement, in which the precipitating electrode is a tube beingelliptical in cross section while finally Fig. 23 shows a modificationof a cylindrical ionization body, which has a number of ionizationelectrodes internally and externally.

In Fig. 1 the electrode plates I and 8 of the charging and precipitatingvoltage respectively are arranged in a conduit 4 for passing the gasesto be purified. Between these plates are arranged in the examples shownrod-shaped electrodes 9 and 10. To these electrodes voltages aresupplied, and the voltage 6 supplied to the charging and precipitatingplates 1 and respectively may be completely separated from the voltage 5supplied to the ionization electrodes 9 and ill or may be inter-linkedtherewith, as shown in Fig. 1.

An ionization electrode or one of the two series (9) of ionizationelectrodes may therefore act simultaneously as an electrode of thecharging and separating voltage respectively. Simple methods ofconnection can then be obtained if the two charging and precipitatingplates are connected up in parallel as in the arrangement shown inFig. 1. If the voltages are supplied to the electrodes separately, it isadvantageous to select by suitable connection, interlinking oftransformers or otherwise the potentials insuch a way that the meanpotential of the ionization electrodes lies between the charging andseparating potentials.

In all these examples the ionization electrodes may be of any desiredform; preferably they will be constructed in the form of rods. Withflowing gases to be purified, these rod-shaped conductors may be laideither longitudinally of or at right angles to the direction in whichthe gas flows between the electrodes of the charging and separatingvoltage respectively. The space or zone included between the chargingand separating electrodes, such as the space or zone between electrodes1 and 8, as shown in Fig. 1, through which flows the gas to be purified,constitutes the charging and separating area or zone, since it is herethat the gas to be purified flows and is charged and in whichnon-gaseous matter is removed or precipitated.

In the embodiment shown in Fig. 1 the two series 9 and ill of ionizationelectrodes are embedded in a layer or plate ll of suitable insulatingmaterial or semi-insulating material. Fig. 2 shows the ionization field,which is produced when voltage is supplied to the series 8 and I D ofconductors. It traverses partly both the solid dielectric and also thegas. If the distance of the linear conductors 8 and III, the thicknessof the plate H and the strength of the voltage are suitably selected,ionization is produced in the gas along the boundary layer between thegas and the badly conducting material, this zone constituting the impactionization area or zone. By suitable selection of the conditions it ispossible to adjust the uniform distribution of the ionization over theentire surface and at the same time to control the intensity thereof. Asa further means of adjustment the selection of the dielectric constantsof the layers, their conductivity and also the shape, kind and nature ofthe boundary surface may serve.

Figs. 3 and 4 show in cross section and elevation a plate H composed ofinsulating material in which the conductors i2, I! of both polarities ofthe ionizer, are embedded on both sides near the surface. The conductorsform a grid or fork and are each connected at one end by means of theconductors l5 and I6 respectively to a series of conductors connected upin parallel. The conductors l1, II which are connected to the crossconnections i5 and I6 respectively and lead to a suitable main 20 act asthe return conductor. If an alternating current voltage is supplied tothe conductors l1, l8, fields are produced, which partially traverse thedielectric, and pass partially on the surface of the insulating layer orplate. If a sumciently high voltage is selected, the socalled polarbrushes or ,iump-over-sparks are produced, which alternately charge anddischarge the two sides of the insulating layer electrically. In thisway the surface of the insulating layer is coated, in the example shown,on both sides with an intense and uniform ionization layer. According tothe selection of the voltage serving for ionization the electrodes ofthe series will be placed more or less close to each other, so that theionization may take place under favourable conditions and with acomparatively small expenditure of energy and that it may uniformlycover the surface of the ionizer.

In order to avoid the risk of sparking across between the electrodes ofdiflerent polarities, the cross connections l5 and I6 may be arranged atsuificiently wide distances from the adJoining edge of the plates l9 andII respectively. The plates may be produced in any desired manner bysimple means. According to the conditions prevailing they may be cast,pressed or formed in any other manner. They may be made of any desiredsize, so that they can directly be adapted to the particular purpose forwhich they are to be used. So, they are particularly suitable asionizers for dust precipitating plants, in which the charging of theparticles to be separated takes place by impact ionization and thestrength of the field required for the impact ionization is produced bymeans of a voltage in a special zone situated at the side of thecharging and separating zones and electrical charge carriers thereby areformed, while one or more other voltages which do not serve forionization convey the charge carriers into the charging zone and thereprecipitate the charged particles. The ionizers according to thisinvention may be made of any desired dimensions for these dustprecipitating p s n be combined of plates so that they can be used fordust precipitating plants of any desired size and for any desiredcondition. )As at the same time an intense ionization is possible, andfavourable conditions result also for the precipitation of the VIIcharged particles, very eflective plants result, which permit theparticles of dust to be separated over a comparatively short course.

Whereas in the embodiment shown in Fig. 3 the conductors lie inside theinsulating layer near the surface thereof, in the example which is shownin Fig. 5 in; cross section, the series of conductors 24, 25 arearranged on the surface.

Fig. 6 shows an example in which the conductors are applied to thesurface preferably as thin strips, in this example in two series 21, 28by a suitable process as indicated above.

Whereas the examples hitherto described show arrangements in which theionizer is constructed towards both sides symmetrically and actssymmetrically, Fig. 7 shows in cross section an example of an ionizer inwhich the ionizing action takes place towards one side only. In thiscase the ionization electrodes consist partly of conductors 3| arrangedwithin the plate at a greater depth and partly of conductors 32 whichlie on the surface of the insulating layer or may also be embeddedtherein near the surface.

Figs. 8 and 9 show in cross section symmetrical arrangements in whichthe ionization electrodes lie partly in the interior of the insulatinglayer in a series (see Fig. 8 or also in two series 36, 31 connected upin parallel for example (see Fig. 9) while another part of theionization electrodes 38, 39 is arranged on the surface of theinsulating layer. In this case conductors arranged on the surface ornear the surface are connected up in parallel across the conductors 40,ll and lead to a conductor 42 of the mains, while the other conductor 43leads to the conductors embedded more deeply in the insulating layer.

In order that the point where the electrical conductors are taken to theconductors which lie deep in the insulating layer, is safeguardedagainst any risk of sparking across, the ends of the conductors 38 and39 respectively-and correspondingly in the other arrangements-may bescreened off by a collar 50 from the part 43 of the middle conductors asshown in perspective in Fig. 10. Instead of this collar the plate ofinsulating material may be thickened at the end or be provided withgrooves or channels, expedients which are all well known per se in hightension practice.

Figs. 11, 12, and 13 show in cross section and elevation respectively anarrangement in which the insulating layer has embedded in it anelectrically conducting layer, for example a hollow space filled withconducting dust or liquid or a plate of electrically conductingmaterial, so that the section between the electrodes on both sides ofthe surface of the insulating layer is divided up by one or eventuallyby a series of conducting layers. In this way the development of thefield at the surface of the ionizer is strengthened and the risk ofsurface discharges or creeping discharges between the conductors ofdifferent polarities is eflectively lessened. These conductors whichdivide up the section between the outer electrodes and which may beconstructed in the form of plates or also rods. grids. nets or the like,may be connected to the voltage or not connected to it. In the exampleshown in Fig. 11 the plate 5| is not connected. while the electrodesconnected to the voltage are formed of the series of electrodes 53, 54,which are located on the surface.

In the embodiment shown in Fig. 12, on the other hand, the plate 52forms one electrode of the ionizer, while the series of electrodes 55,56 connected up in parallel on the surface of the UHHHHBF insulatingplate form the second electrode of the ionizer. The connection to theplate may be made in this example by making the plate emerge at the sideat 58 from the insulator as shown in Fig. 13 as an elevation of Fig. 12.

In those symmetrical arrangements in which conductors are arranged at adepth in the insulating layer, the individual conductors will generallybe arranged in the same kind on the surface of the insulating layer, asshown by the conductors 3B, 38 in Figs. 8 and 9, while in cases in whichno conductors are embedded in the insulating layer, but only conductorsarranged on or near the surface of the insulating layer are used, theconductors may be echeloned, as shown by the series of conductors l2, l3and 23, 24, and 21, 28 respectively in Figs. 3 to 6.

Fig. 14 shows the arrangement of an ionizer of the kind according tothis invention, for example as shown in Fig. 6, in a dust precipitatingplant. The precipitating plates are denoted by 65, 66. A continuousvoltage or a slowly pulsating alternating voltage is supplied to themfrom the main 10 while the ionizer is fed from the alternating currentmain 2D. In the example shown the voltages are so interlinked that themain potential of the ionizer differs from the potential of theseparating plates, so that a continuous voltage field exists between theionizer and the separating plates. This is obtained by interlinkingcontinucus voltage and ionizer alternating voltage. For this purpose forexample in the arrangements of Figs. 3, 4, 5, 6, 7, 11, and 14 the onecontinuous voltage pole may be laid at the middle of the secondarywinding of the ionizer transformer; in the arrangement shown in Figs. 8,9, l2, and 13, on the other hand, the continuous voltage pole may betaken to the outer coatings of the ionizer plates for example.

The charge carriers produced by the ionizer plates by impact ionizationare conveyed by the field which exists between the electrodes 65, 56 andis superimposed upon the ionization field, through the charging arealying at the side of the ionizing area towards the precipitatingelectrodes. During this way of the carriers of electricity the particleswhich float in the gas flowing between the precipitating electrodes, forexample in the direction in ate dby the arrows I I, will be charged andpasgiinderithe influence oi. the field existing between the electrodes65. 6G or a special field, to the precipitating electrodes.

Instead of the arrangement of ionizer illustrated in Fig. 14 any otherdesired arrangement of ionizer according to the present invention may beused, just as the ionizers according to this invention may be used inany kind of dust precipitating plants or in arrangements working undersimilar conditions.

Figs. 15 to 23 show further developments of the invention, which areparticularly valuable when great demands are made on the mechanicalstrength and in particular on the power to resist temperatures of theelements used in the arrangement, when for example chambers of largedimensions are used for treatment or when the purification of gases at ahigh temperature, such as flue gases for example, has to be carried out.

According to this development of the invention the layer of insulatingmaterial, which separates the ionization electrodes of the differentpolarities, is made cylindrical and in particular tubular. Cylinders ortubes of high grade ceramic material, such as porcelain or difflcultlyfusible glasses or other fusible substances may be employed for thelayer which separates the ionization electrodes; the usual insulatingproducts of electrical industry, particularly mica prodnets of allkinds, artificial resins, particularly condensation products likebalrelite, may be used also.

The tubular insulating bodies surround, in a preferred embodiment of theinvention, the ionization electrode of the one polarity as a core or aninternal lining, while the conductors of the other polarity, which arepreferably made in the form of linear conductors, are arranged on theouter surface of the insulating body. The external conductors may beconstructed in any desired manner and be attached to the outer surfaceof the insulating tubes or cylinders in any desired way. The conductors,preferably linear ones, may also surround singly or in numbers and inthe form of rings or helically the outer surface of the cylinder or tubeof insulating material or any other body.

Fig. 15 shows in cross section and Fig. 16 in perspective, anarrangement according to this invention, in which ionization bodiesaccording to this invention are arranged in numbers between plate-shapedelectrodes 00, along a plane parallel with the plate-shapedprecipitating electrodes and over which plane they are distributed. Thetubular, insulating intermediate layers 82 have a rod-shaped core 03 ofconducting material such as copper, bronze, or the like for example,which are connected by the conductor 88 to one terminal of a hightension alternating current main 90 for example. on the outside of thetubes 82 of insulating material are each arranged two conductors 84, 05which lie diametrically opposite each other and which being connected inparallel with each other are connected to the other terminal of thealtemating current main 00 by the conductor 09. Between the electrode 83on the one hand and 84, 85 on the other hand a strong ionization fieldIs thus produced, which fills the portion of space lying at the side ofthe charging and separating areas and being formed by the layer ofionization bodies distributed over a surface. By means of the continuouscurrent field produced between the precipitating plates 00, 0| connectedin parallel and the layer of the ionization body by a continuous currentthe electrons or other charge carriers formed at the ionization bodieswill be conveyed into the space charging area at the side of this layer,and will charge the particles floating in the gas which fiows forexample in the direction indicated by the arrow, which particles willthen be precipitated on the precipitatin electrodes under the action ofthe fields wh ch exists in this area.

Whereas in the example shown in Figs. 15 and 16 the conductors arrangeddiametrically on the outer surface of the insulation tubes are arrangedin such a way that their plane of connection lies in the plane of theionization bodies, Fig. 17 shows an arrangement in which the plane ofconnection of these electrodes 00, 95 is at right angles to the plane ofthe ionization bodies. This arrangement has the advantage that the pointat which the intense ionization is produced lies nearer to that areawithin which the particles floating in the gas are to be charged. Inthis case as above described, the ends of the conductors may also beconveniently staggered relatively to the ends of the insulating tubes,as is shown in perspective in Fig. 16, so as to provide cross overs oflarge area between the electrodes of both polarites.

These arrangements shown in Figs. 15 to 23 can also be used for everykind of construction of precipitating electrodes whether they beplateshaped or cylindrical or of any other desired form. Figs. 18 and 19show two arrangements, in which a cylindrical precipitating electrode 96receives the cylindrical ionization body concentrically. The inventionis not limited to arranging only one insulating body between thisprecipitating tube. The ionization bodies may also be provided inanydesired number.

In the embodiment shown in Fig. 18 an ionization body of the kinddescribed with reference to Figs. 15 to 17 is illustrated.

Fig. 19 shows an ionization body for large capacities. In this case theionization tube 95 has an inner lining I00 composed of conductingmaterial, while the outer conductors of the other polarity, which extendin the direction of the axis of the tube, are arranged in numbers acrossthe periphery of the insulating tube. The external conductors may extendparallel with the axis of the tube, but they may also be arranged inanother desired form on the surface of the insulating tube or cylinder.

Fig. 20 shows an example, in which the outer electrodes "II, of whichthere are a number in the example illustrated, surround the insulatingtube in the form of rings. The outer electrodes, which are preferably oflinear form, may also as Fig. 21 shows for an electrode I02, be woundhelically round the insulating tube 82.

Fig. 22 shows the example of an arrangement in which the ionizationelectrodes I04 are arranged inside a cylinder I03 of elliptical form.

The internal electrode, too, may be arranged in another way thanhitherto shown. Thus for example a number of core electrodes may beembedded in the cylindrical body of insulating material, as shown in theexample illustrated in Fig. 23. In this case ten outer electrodes I05are shown, which cooperate with five internal electrodes I06.

The shape of the internal electrode need not be cylindrical. Theinternal electrodes may also be of any other desired cross sectionalform such for example as quadratic, polygonal, cruciform, or the like.

It will be understood that the invention is not limited to theembodiments described and illustrated by way of example and that variousstructural changes and modifications may be made without departing fromthe spirit of our invention, and we desire therefore that the appendedclaims should be construed in the light of prior knowledge.

Having thus described our invention, what we claim as new and desire tosecure by Letters Patent, is:-

I. In apparatus for the ionization of gases, particularly for theelectric purification thereof, ionization electrodes, a layer ofinsulating material continuous between and separating the ionizationelectrodes, voltage means for inducing an electric field between saidelectrodes and substantially at the surface of said insulating layer andalong said surface, said surface being of substantially greater areathan the exposed electrode area, said field having a substantiallysurface-like form and being of sumcient strength to produce ionizationand thus electric charge carriers, other voltage means for inducing asecond electric field in a space adjacent said first field, said secondfield being for propelling said charge carriers into the stream of gasto be cleaned and for charging the particles suspended within the gasand for eventually precipitating them.

2. In apparatusfor the ionization of gases, particularly for theelectric purification thereof, ionization electrodes, a layer ofinsulating material continuous between and separating the ionizationelectrodes, said layer of insulating material being of greater area thanthe exposed ionization electrode area, voltage means for inducing anelectric field between said electrodes and substantially at the surfaceof said insulating layer and along said surface, said field having asubstantially surface-like form and being of sufficient strength toproduce ionization and thus electric charge carriers, other voltagemeans for inducing a second electric field in a space adjacent saidfirst field, said second field being for propelling said charge carriersinto the stream of gas to be cleaned and for charging the particlessuspended within the gas and for eventually precipitating them. one ofthe electrodes of said second field having a surface substantiallyparallel to an ionization surface of the insulating material, anionization electrode of one polarity being arranged at said ionizationsurface, said second electric field being established between said oneof the electrodes of the second field and the last mentioned ionizationelectrode, and said field being adapted to attract particles charged bysaid charge carriers whereby said charged particles are deposited atsaid electrode.

3. In electrical apparatus for the ionization of gases, a conduit forpassing gases, insulating means in the conduit presenting a surfaceextending longitudinally of the conduit, electrodes of difierentpolarities associated with said insulating means for establishing anionizing field contiguous to said surface, said surface substantiallycompletely separating electrically the electrodes of differentpolarities and other electrical means of different polarities andincluding an electrode substantially paralleling and spaced from saidsurface, the space between the last mentioned electrode and. saidsurface constituting a charging and precipitating zone whereinnon-gaseous matter is removed and precipitated from gaseous matterpassed through said conduit.

4. In electrical apparatus for the ionization of gases, a conduit forpassing gases, means for LX'dlliiuU establishing in said conduit anelectrical ionizing field extending in a plane substantially parallel tothe conduit walls and paralleling the path of gases flowing by saidionizing field, and other means for establishing in said conduit asecond electrical field with lines of force extending substantiallytransversely of the path of gases passing through said conduit, saidsecond electrical field directing charges and/or charged particlesthrough said second electrical field and the gases passing therethrough.

5. In apparatus of the class described, a conduit for passing gases tobe purified, at least a portion of said conduit comprising an electrodeand presenting an electrode surface substantially parallel to the pathof gases passing through said conduit, means including said electrodefor setting up an electric field with lines of force traversing saidpath of gases for precipitating and depositing charged particles fromsaid gases, a stationary body of insulating material in said conduit andpresenting a surface substantially parallel thereto and spacedtherefrom, and means separate from said first mentioned means andincluding a pair of electrodes associated with said stationary body ofinsulating material for setting up a second electric field with lines offorce substantially parallel to said path of gases, said pair ofelectrodes being completely separated electrically by said stationarybody of insulating material, and said second electric field being ofsufilcient strength to effect ionization independently of the firstmentioned electric field.

6. In apparatus for the ionization of gases, particularly for theelectrical purification thereof, an insulator adjacent to which gases tobe purified may be passed, a pair of electrodes associated with andsubstantially completely separated electrically from each other by theinsulator, the surface of the insulator adjacent one electrode beingsubstantially greater than the exposed area of said electrode, wherebythe impression of diflerent electrical potentials upon said electrodeswill cause a field to be formed substantially upon the surface of theinsulator for the production of electric charge carriers, and othermeans of producing potentials independent from said first mentionedpotentials for propelling said charge carriers away from said surface.

GEORG BRION. ARTHUR JOHANNES KRUTZSCH.

